System for additively manufacturing composite structure

ABSTRACT

A system is disclosed for use in additively manufacturing a structure. The system may include a print head configured to discharge a material, and a support connected to and configured to move the print head during discharging to fabricate a structure. The system may also include a receiver mounted to the print head and configured to generate a signal indicative of at least one of a shape, a size, and a location of the discharged material, and a processor in communication with the receiver and the support. The processor may be configured to generate a data cloud of the structure fabricated by the additive manufacturing system based on the signal and based on a known position of the receiver at a time of signal generation. The processor may also be configured to make a comparison of the data cloud and a virtual model of the structure during discharging, and to selectively affect discharging based on the comparison.

RELATED APPLICATION

This application is based on and claims the benefit of priority fromU.S. Provisional Application No. 62/797,078 that was filed on Jan. 25,2019, the contents of which are expressly incorporated herein byreference.

TECHNICAL FIELD

The present disclosure relates generally to a manufacturing system and,more particularly, to a system for additively manufacturing compositestructures.

BACKGROUND

Continuous fiber 3D printing (a.k.a., CF3D®) involves the use ofcontinuous fibers embedded within a matrix discharging from a moveableprint head. The matrix can be a traditional thermoplastic, a powderedmetal, a liquid resin (e.g., a UV curable and/or two-part resin), or acombination of any of these and other known matrixes. Upon exiting theprint head, a head-mounted cure enhancer (e.g., a UV light, anultrasonic emitter, a heat source, a catalyst supply, etc.) is activatedto initiate and/or complete curing of the matrix. This curing occursalmost immediately, allowing for unsupported structures to be fabricatedin free space. When fibers, particularly continuous fibers, are embeddedwithin the structure, a strength of the structure may be multipliedbeyond the matrix-dependent strength. An example of this technology isdisclosed in U.S. Pat. No. 9,511,543 that issued to Tyler on Dec. 6,2016 (“the '543 patent”).

Although CF3D® provides for increased strength, compared tomanufacturing processes that do not utilize continuous fiberreinforcement, improvements can be made to the structure and/oroperation of existing systems. For example, the disclosed additivemanufacturing system is uniquely configured to provide theseimprovements and/or to address other issues of the prior art.

SUMMARY

In one aspect, the present disclosure is directed to an additivemanufacturing system for use in discharging a continuous reinforcement.The additive manufacturing system may include a print head configured todischarge a material, and a support connected to and configured to movethe print head during discharging to fabricate a structure. The systemmay also include a receiver mounted to the print head and configured togenerate a signal indicative of at least one of a shape, a size, and alocation of the discharged material, and a processor in communicationwith the receiver and the support. The processor may be configured togenerate a data cloud of the structure fabricated by the additivemanufacturing system based on the signal and based on a known positionof the receiver at a time of signal generation. The processor may alsobe configured to make a comparison of the data cloud and a virtual modelof the structure during discharging, and to selectively affectdischarging based on the comparison.

In another aspect, the present disclosure is directed to a method ofadditively manufacturing a structure. The method may include discharginga material from a print head, and moving the print head duringdischarging to fabricate the structure. The method may further includegenerating a signal indicative of at least one of a shape, a size, and alocation of the discharged material, and generating a data cloud of thestructure during discharging based on the signal. The method may furtherinclude making a comparison of the data cloud and a virtual model of thestructure during discharging, and selectively affecting dischargingbased on the comparison.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic illustration of an exemplary disclosed additivemanufacturing system;

FIG. 2 is a diagrammatic illustrations of an exemplary disclosed headportion of the system of FIG. 1;

FIGS. 3 and 4 are schematic illustrations of an exemplary controlportion of the system of FIG. 1; and

FIG. 5 is a flowchart depicting an exemplary disclosed method ofoperating the additive manufacturing system of FIG. 1.

DETAILED DESCRIPTION

FIG. 1 illustrates an exemplary system 10, which may be used tomanufacture a composite structure 12 having any desired shape. System 10may include a support 14 and deposition head (“head”) 16. Head 16 may becoupled to and moved by support 14. In the disclosed embodiment of FIG.1, support 14 is a robotic arm capable of moving head 16 in multipledirections during fabrication of structure 12. Support 14 mayalternatively embody a gantry (e.g., an overhead-bridge or single-postgantry) or a hybrid gantry/arm also capable of moving head 16 inmultiple directions during fabrication of structure 12. Although support14 is shown as being capable of 6-axis movements, it is contemplatedthat support 14 may be capable of moving head 16 in a different manner(e.g., along or around a greater or lesser number of axes). In someembodiments, a drive may mechanically couple head 16 to support 14, andinclude components that cooperate to move portions of and/or supplypower or materials to head 16.

As shown in FIG. 2, structure 12 may include an internal skeleton 17that is covered by an external skin 19. In some embodiments, thesecomponents of structure 12 may be fabricated separately and subsequentlyjoined (e.g., via mechanical fastening, chemical adhesion, molecularbonding, etc.). For example, skeleton 17 may be fabricated from a firstadditive manufacturing process, while skin 19 may be manufactureddirectly onto skeleton 17 from a second and different additivemanufacturing process. It is contemplated that both skeleton 17 and skin19 could be manufactured separately from the same additive manufacturingprocess, if desired. In other embodiments, the components may befabricated together as an integral monolithic structure (e.g., astructure that cannot be disassembled without at least somedestruction).

Head 16 may be configured to receive or otherwise contain a matrix Mthat can be used to fabricate one or both of skeleton 17 and skin 19.The matrix may include any types or combinations of materials (e.g., aliquid resin, such as a zero-volatile organic compound resin, a powderedmetal, etc.) that are curable. Exemplary resins include thermosets,single- or multi-part epoxy resins, polyester resins, cationic epoxies,acrylated epoxies, urethanes, esters, thermoplastics, photopolymers,polyepoxides, thiols, alkenes, thiol-enes, and more. In one embodiment,the matrix inside head 16 may be pressurized (e.g., positively and/ornegatively), for example by an external device (e.g., by an extruder, apump, etc.—not shown) that is fluidly connected to head 16 via acorresponding conduit (not shown). In another embodiment, however, thepressure may be generated completely inside of head 16 by a similar typeof device. In yet other embodiments, the matrix may be gravity-fed intoand/or through head 16. For example, the matrix may be fed into head 16,and pushed or pulled out of head 16 along with one or more continuousreinforcements. In some instances, the matrix inside head 16 may need tobe kept cool and/or dark in order to inhibit premature curing orotherwise obtain a desired rate of curing after discharge. In otherinstances, the matrix may need to be kept warm and/or illuminated forsimilar reasons. In either situation, head 16 may be speciallyconfigured (e.g., insulated, temperature-controlled, shielded, etc.) toprovide for these needs.

The matrix may be used to at least partially coat any number ofcontinuous reinforcements (e.g., separate fibers, tows, rovings, socks,and/or sheets of continuous material) R and, together with thereinforcements, make up a portion (e.g., a wall) of composite structure12. The reinforcements may be stored within or otherwise passed throughhead 16. When multiple reinforcements are simultaneously used, thereinforcements may be of the same material composition and have the samesizing and cross-sectional shape (e.g., circular, square, rectangular,etc.), or a different material composition with different sizing and/orcross-sectional shapes. The reinforcements may include, for example,carbon fibers, vegetable fibers, wood fibers, mineral fibers, glassfibers, plastic fibers, metallic fibers, optical fibers (e.g., tubes),etc. It should be noted that the term “reinforcement” is meant toencompass both structural and non-structural (e.g., functional) types ofcontinuous materials that are at least partially encased in the matrixdischarging from head 16.

The reinforcements may be at least partially coated with the matrixwhile the reinforcements are inside head 16, while the reinforcementsare being passed to head 16, and/or while the reinforcements aredischarging from head 16. The matrix, dry (e.g., unimpregnated)reinforcements, and/or reinforcements that are already exposed to thematrix (e.g., pre-impregnated reinforcements) may be transported intohead 16 in any manner apparent to one skilled in the art. In someembodiments, a filler material (e.g., chopped fibers, nano particles ortubes, etc.) and/or additives (e.g., thermal initiators, UV initiators,etc.) may be mixed with the matrix before and/or after the matrix coatsthe continuous reinforcements.

One or more cure enhancers (e.g., a UV light, an ultrasonic emitter, alaser, a heater, a catalyst dispenser, etc.) 18 may be mounted proximate(e.g., within, on, and/or adjacent) head 16 and configured to enhance acure rate and/or quality of the matrix as it is discharged from head 16.Cure enhancer 18 may be controlled to selectively expose portions ofstructure 12 to energy (e.g., UV light, electromagnetic radiation,vibrations, heat, a chemical catalyst, etc.) during material dischargeand the formation of structure 12. The energy may trigger a chemicalreaction to occur within the matrix, increase a rate of the chemicalreaction, sinter the matrix, harden the matrix, solidify the material,polymerize the material, or otherwise cause the matrix to cure as itdischarges from head 16. The amount of energy produced by cure enhancer18 may be sufficient to cure the matrix before structure 12 axiallygrows more than a predetermined length away from head 16. In oneembodiment, structure 12 is completely cured before the axial growthlength becomes equal to an external diameter of the matrix-coatedreinforcement.

The matrix and/or reinforcement may be discharged from head 16 via anynumber of different modes of operation. In a first example mode ofoperation, the matrix and/or reinforcement are extruded (e.g., pushedunder pressure and/or mechanical force) from head 16 as head 16 is movedby support 14 to create features of structure 12. In a second examplemode of operation, at least the reinforcement is pulled from head 16,such that a tensile stress is created in the reinforcement duringdischarge. In this second mode of operation, the matrix may cling to thereinforcement and thereby also be pulled from head 16 along with thereinforcement, and/or the matrix may be discharged from head 16 underpressure along with the pulled reinforcement. In the second mode ofoperation, where the matrix is being pulled from head 16 with thereinforcement, the resulting tension in the reinforcement may increase astrength of structure 12 (e.g., by aligning the reinforcements,inhibiting buckling, etc.) after curing of the matrix, while alsoallowing for a greater length of unsupported structure 12 to have astraighter trajectory. That is, the tension in the reinforcementremaining after curing of the matrix may act against the force ofgravity (e.g., directly and/or indirectly by creating moments thatoppose gravity) to provide support for structure 12.

The reinforcement may be pulled from head 16 as a result of head 16being moved by support 14 away from an anchor point (e.g., a print bed,an existing surface of structure 12—shown in FIG. 2, a fixture 20—shownin FIG. 1, etc.). In particular, at the start of structure formation, alength of matrix-impregnated reinforcement may be pulled and/or pushedfrom head 16, deposited onto the anchor point, and at least partiallycured, such that the discharged material adheres (or is otherwisecoupled) to the anchor point. Thereafter, head 16 may be moved away fromthe anchor point, and the relative movement may cause the reinforcementto be pulled from head 16. It is contemplated that the movement ofreinforcement through head 16 may be selectively assisted via one ormore internal feed mechanisms, if desired. However, the discharge rateof reinforcement from head 16 may primarily be the result of relativemovement between head 16 and the anchor point, such that tension iscreated within the reinforcement. As discussed above, the anchor pointcould be moved away from head 16 instead of or in addition to head 16being moved away from the anchor point.

As further illustrated in FIG. 2, head 16 may include, among otherthings, an outlet 22 and a matrix reservoir 24 located upstream ofoutlet 22. In one example, outlet 22 is a single-channel nozzleconfigured to discharge composite material having a generally circular,tubular, or rectangular cross-section. The configuration of head 16,however, may allow outlet 22 to be swapped out for another outlet (e.g.,a nozzle-less outlet) that discharges multiple channels of compositematerial having different shapes (e.g., a flat or sheet-likecross-section, a multi-track cross-section, etc.). Fibers, tubes, and/orother reinforcements may pass through matrix reservoir 24 and be wetted(e.g., at least partially coated and/or fully saturated) with matrixprior to discharge.

Any number of separate computing devices 26 may be used to design and/orcontrol the wetting, placement, curing, tension, etc. of reinforcementswithin structure 12 and/or to analyze characteristics of structure 12before, during, and/or after fabrication. An exemplary computing device26 is illustrated in detail in FIG. 3. As shown in this figure,computing device 26 may include, among other things, a display 34, oneor more processors 36, any number of input/output (“I/O”) devices 38,any number of peripherals 40, and one or more memories 42 for storingprograms 44 and data 46. Programs 44 may include, for example, anynumber of design and/or printing apps 48 and an operating system 50.

Display 34 of computing device 26 may include a liquid crystal display(LCD), a light emitting diode (LED) screen, an organic light emittingdiode (OLED) screen, and/or another known display device. Display 34 maybe used for presentation of data under the control of processor 36.

Processor 36 may be a single or multi-core processor configured withvirtual processing technologies, and use logic to simultaneously executeand control any number of operations. Processor 36 may be configured toimplement virtual machine or other known technologies to execute,control, run, manipulate, and store any number of software modules,applications, programs, etc. In addition, in some embodiments, processor36 may include one or more specialized hardware, software, and/orfirmware modules (not shown) specially configured with particularcircuitry, instructions, algorithms, and/or data to perform functions ofthe disclosed methods. It is appreciated that other types of processorarrangements could be implemented that provide for the capabilitiesdisclosed herein.

Memory 42 can be a volatile or non-volatile, magnetic, semiconductor,tape, optical, removable, non-removable, or other type of storage deviceor tangible and/or non-transitory computer-readable medium that storesone or more executable programs 44, such as data capture, analysis,and/or printing apps 48 and operating system 50. Common forms ofnon-transitory media include, for example, a flash drive, a flexibledisk, a hard disk, a solid state drive, magnetic tape or other magneticdata storage medium, a CD-ROM or other optical data storage medium, anyphysical medium with patterns of holes, a RAM, a PROM, an EPROM, aFLASH-EPROM or other flash memory, NVRAM, a cache, a register or othermemory chip or cartridge, and networked versions of the same.

Memory 42 may store instructions that enable processor 36 to execute oneor more applications, such as design, analysis, and/or fabrication apps48, operating system 50, and any other type of application or softwareknown to be available on computer systems. Alternatively oradditionally, the instructions, application programs, etc. can be storedin an internal and/or external database (e.g., a cloud storagesystem—not shown) that is in direct communication with computing device26, such as one or more databases or memories accessible via one or morenetworks (not shown). Memory 42 can include one or more memory devicesthat store data and instructions used to perform one or more features ofthe disclosed embodiments. Memory 42 can also include any combination ofone or more databases controlled by memory controller devices (e.g.,servers, etc.) or software, such as document management systems,Microsoft SQL databases, SharePoint databases, Oracle™ databases,Sybase™ databases, or other relational and/or non-relational databases.

In some embodiments, computing device 26 is communicatively connected toone or more remote memory devices (e.g., remote databases—not shown)through a network (not shown). The remote memory devices can beconfigured to store information that computing device 26 can accessand/or manage. By way of example, the remote memory devices could bedocument management systems, Microsoft SQL database, SharePointdatabases, Oracle™ databases, Sybase™ databases, Cassandra, HBase, orother relational or non-relational databases or regular files. Systemsand methods consistent with disclosed embodiments, however, are notlimited to separate databases or even to the use of a database.

Programs 44 may include one or more software or firmware modules causingprocessor 36 to perform one or more functions of the disclosedembodiments. Moreover, processor 36 can execute one or more programslocated remotely from computing device 26. For example, computing device26 can access one or more remote programs that, when executed, performfunctions related to disclosed embodiments. In some embodiments,programs 44 stored in memory 42 and executed by processor 36 can includeone or more of design, fabrication, and/or analysis apps 48 andoperating system 50. Apps 48 may cause processor 36 to perform one ormore functions of the disclosed methods.

Operating system 50 may perform known operating system functions whenexecuted by one or more processors such as processor 36. By way ofexample, operating system 50 may include Microsoft Windows™, Unix™,Linux™, OSX™, and IOS™ operating systems, Android™ operating systems, oranother type of operating system 50. Accordingly, disclosed embodimentscan operate and function with computer systems running any type ofoperating system 50.

I/O devices 38 may include one or more interfaces for receiving signalsor input from a user and/or system 10, and for providing signals oroutput to system 10 that allow structure 12 to be printed. For example,computing device 26 can include interface components for interfacingwith one or more input devices, such as one or more keyboards, mousedevices, and the like, which enable computing device 26 to receive inputfrom a user.

Peripheral device(s) 40 may be standalone devices or devices that areembedded within or otherwise associated with other components (e.g.,support 14 and/or head 16) of system 10 and used during fabrication ofstructure 12. As shown in FIG. 4, peripherals 40 can embody inputdevices (e.g., one or more sensors, such as tension sensors, positionsensors, pressure sensors, temperature sensors, flow sensors, continuitysensors, humidity sensors, rotary encoders, optical scanners, and othersensors known in the art) 40A and/or output devices (e.g., one or moreactuators, such as a matrix supply, a fiber supply, a cooling fan, apump, cure enhancer(s) 18, a positioning motor, a cutter, a splicer, aweaving mechanism, a fiber guide, a mixer, a feed roller, a compactor, afriction tensioner, etc.) 40B. In some embodiments, peripherals 40 may,themselves, include one or more processors, a memory, and/or atransceiver. When peripheral device(s) 40 are equipped with a dedicatedprocessor and memory, the dedicated processor may be configured toexecute instructions stored on the memory to receive commands fromprocessor 36 associated with video, audio, other sensory data, controldata, location data, etc., including capture commands, processingcommands, motion commands, and/or transmission commands. The transceivermay include a wired or wireless communication device capable oftransmitting data to or from one or more other components in system 10.In some embodiments, the transceiver can receive data from processor 36,including instructions for sensor and/or actuator activation and for thetransmission of data via the transceiver. In response to the receivedinstructions, the transceiver can packetize and transmit data betweenprocessor 36 and the other components.

Returning to FIG. 3, design, fabrication, and/or analysis apps 48 maycause computing device 26 to perform methods related to generating,receiving, processing, analyzing, storing, and/or transmitting data inassociation with operation of system 10 and correspondingdesign/fabrication/analysis of structure 12. For example, apps 48 may beable to configure processor 36 to perform operations including:displaying a graphical user interface (GUI) on display 34 for receivingdesign/control instructions and information from the operator of system10; capturing sensory data associated with system 10 (e.g., via inputdevices 40A); receiving instructions via I/O devices 38 and/or the userinterface regarding specifications, desired characteristics, and/ordesired performance of structure 12; processing the controlinstructions; generating one or more possible designs of and/or plansfor fabricating structure 12; analyzing and/or optimizing the designsand/or plans; providing recommendations of one or more designs and/orplans; controlling system 10 to fabricate a recommended and/or selecteddesign via a recommended and/or selected plan; monitoring and/oranalyzing the fabrication in real or near-real time; and/or providingfeedback and adjustments (e.g., via output devices 40 b) to system 10for improving current and/or future fabrications.

Returning to FIG. 2, an exemplary input device 40A is illustrated asbeing operatively connected to head 16. In this example, input device40A includes at least one receiver (e.g., a camera, a light sensor,etc.) 30 and one or more sources of visible and/or invisible light(e.g., a laser and/or other sources) 32 that are together configured togenerate signals indicative of an actual shape, size, and/or position ofcomposite material deposited by outlet 22. In some instances, receiver30 and light source 32 are packaged together as a single unit. In thesame or other instances, light source 32 may be cure enhancer 18 (e.g.,a single source that performs both functions).

Receiver(s) 30 may be located at a trailing side of outlet 22 duringoperation, so as to capture and/or record the position of compositematerial being extruded by outlet 22. In one example, receiver(s) 30 arefurther located at a trailing side of any associated compactor, wiper,and/or other trailing component. It is contemplated, however, that oneor more of receiver(s) 30 could be located between any of thesecomponents, if desired.

In one embodiment, receiver(s) 30 may be configured to capture surfaceimages of the deposited material, while the light source(s) 32 arecontinuously energized or selectively flashed on-and-off. Surfacefeatures may be recognized from the images (e.g., by computing device 26via image recognition software) and/or compiled into one or morecomprehensive maps (e.g., a data cloud 35) of the material surface thatare stored within memory 42. In another embodiment, signals indicativeof the surface geometry are generated in response to reflected light,sound waves, magnetic waves, etc. being detected by receiver(s) 30. Forexample, a laser-type light or other energy source 32 may be configuredscan the material surface, while receiver(s) 30 generate a plurality ofstripes and/or points associated with light or energy reflecting off thesurface. These stripes and/or points can also be collected as a cloud ofdata. Signals generated by receiver(s) 30 may be directed to computingdevice 26 for further processing. It is contemplated that the cloud datamay be generated continuously during material deposition (e.g., at a setfrequency) or only periodically to help reduce processing requirements.In addition, it is contemplated that the frequency of data generationmay be dynamically adjusted, if desired, to improve resolution in thedata cloud at particular locations.

Data cloud 35 may be utilized for many purposes. For example, data cloud35 may be used to compare an actual surface of structure 12 to a modeledsurface stored within memory 42, and to make on-the-fly adjustments tosystem 10 (e.g., via selective activation of output devices 40 b toreduce differences. This comparison may also allow for decisions to bemade regarding use or discard of structure 12. In another example, datacloud 35 of skeleton 17 may allow for custom tailoring of skin 19 and/orneeded preparation (e.g., trimming or additional deposit) for skinning.An associated skinning tool path of head 16 (or another end effector—notshown) may be modified or even generated solely (e.g., without referenceto the original model) based on data cloud 35.

FIG. 5 illustrates an exemplary method of operating system 10, which maybe regulated by computing device 26. FIG. 5 will be discussed in greaterdetail in the following section to further illustrate the disclosedconcepts.

INDUSTRIAL APPLICABILITY

The disclosed system may be used to manufacture composite structureshaving any desired cross-sectional shape and length. The compositestructures may include any number of different fibers of the same ordifferent types and of the same or different diameters, and any numberof different matrixes of the same or different makeup. Operation ofsystem 10 will now be described in detail.

At a start of a manufacturing event, information regarding a desiredstructure 12 may be loaded into system 10 (e.g., into computing device26 that is responsible for regulating operations of support 14 and/orhead 16) (Step 500). This information may include, among other things, avirtual model of structure 12, including skeleton 17 and/or skin 19(referring to FIG. 2). It is contemplated that the model couldalternatively or additionally be created by a user via computing device26, if desired. It is also contemplated that the model and otherassociated information (e.g., printing parameters) may alternatively oradditionally be loaded into and/or modified by system 10 at differenttimes and/or continuously during the manufacturing event, if desired.Based on the model, one or more different reinforcements and/or matrixmaterials may be installed and/or continuously supplied into system 10.

The virtual model and associated component information may then be usedto initiate printing of structure 12 (e.g., of skeleton 17) and/orotherwise control operation of system 10 (Step 505). For example, thein-situ wetted reinforcements may be pulled and/or pushed from outlet 22of head 16 as support 14 selectively moves (e.g., based on knownkinematics of support 14 and geometry of structure 12 known from themodel), such that the resulting structure 12 is fabricated as desired.

During and/or after fabrication of structure 12 computing device 26(e.g., processor 36) may generate data cloud 35 based on signalsreceived from input device(s) 40 a (e.g., from receiver 30) and knownpositions of input device(s) 40 a (e.g., based on kinematics of support14 and known spatial relationship(s) of input device(s) 40 a to support14) at a time of signal generation (Step 510). Data cloud 35 mayincludes images, points, lines, contours, and/or other featuresindicative of surface geometry of skeleton 17. For example, data cloud35 may be representative of three-dimensional locations of compositematerial within structure 12. The locations may be associated with theentire structure 12, only surfaces of structure 12, and/or onlyparticular features (e.g., at critical locations where high accuracy isrequired). The creation of data cloud 35 may be completed using, forexample, one or more of programs 44 (e.g., apps 48) stored within memory42

Processor 36 may then be configured to compare data cloud 35 with thevirtual model of structure 12 to determine differences therebetween(Step 515). This comparison may be completed throughout fabrication ofstructure 12, only after particular features have been completed, and/orafter fabrication has terminated. When the differences are less than afirst threshold (e.g., when the differences are low enough as to notinterfere with fabrication of skin 19 and/or functionality of structure12), processor 36 may determine if fabrication of skeleton 17 iscomplete (Step 520). Control may cycle back to Step 510 until processor36 determines that fabrication has been completed.

When processor 36 determines at Step 520 that fabrication of structure12 has been completed, processor 36 may initiate printing of skin 19(Step 525). It is contemplated that skinning may be initiated as soon asa particular feature of skeleton 17 is complete or when all of skeleton17 is complete. It is also contemplated that, in some embodiment,structure 12 may not include skin and instead include another feature tobe fabricated (e.g., via different materials and/or a differentprocess). In these embodiments, fabrication of the additional featuremay instead be initiated at Step 525.

Throughout or only at conclusion of structure fabrication, processor 36may display results of the fabrication to a user of system 10 (Step530). For example, processor 36 may cause the virtual model received atStep 500 and/or a representation of data cloud 35 to be shown on the GUIof display 34 (referring to FIG. 3). In one embodiment, the model anddata cloud representation may be overlaid such that any differences maybe visually discerned. For example, the differences may be exaggerated,highlighted, color-coded, etc. such that the user may be made aware ofthe locations and magnitudes of the differences.

Returning to Step 515, when the differences between the virtual modeland data cloud 35 exceed the first threshold, processor 36 may comparethe differences to a second threshold (Step 540). The second thresholdmay be associated with acceptability of structure 12 and may, in someinstances be customizable by a user of system 10. When the differencesexceed the second threshold, structure 12 may be discarded and/oroperational parameters (e.g., matrix parameters, reinforcementparameters, compaction parameters, cure energy parameters, supportmovement parameters, etc.) may be adjusted (Step 535) in preparation fora next fabrication event. Control may then proceed to Step 530. Forexample, processor 36 may terminate material discharge from head 16 andgenerate an electronic flag indicating that structure 12 has failedautomatic inspection and should be manually inspected, repaired, and/ordiscarded.

Returning to Step 540, when processor 36 determines that the differencesbetween the virtual model and the data cloud 35 exceed the firstthreshold, but not the second threshold, processor 36 may modify thevirtual model of skin 19 (Step 545). In particular, skin 19 mayoriginally be modeled to overlay perfectly a perfectly fabricatedskeleton. And depending on printing accuracies, even a perfectlyfabricated skin may not properly engage and/or bond to a less-thanperfectly fabricated skeleton. To accommodate for system inaccuracies,the skin model may be modified to match the contours of theas-fabricated skeleton. This may include, for example, modifications totool paths, modifications to reinforcement tension levels, modificationsto materials, modifications, to speeds and/or cure prescriptions, etc.Control may then proceed from Step 545 to Step 520.

It is contemplated that, at Step 510, an alternative process mayselectively be implemented. For example, control may pass from Step 510to Step 550, instead of to Step 515. That is, the skin model may notactually be generated until after the comparison of the skeleton modelwith data cloud 35, regardless of any comparisons. This may reduceprocessing time and/or effort when compared with first generation andthen modification of the skin model.

It is contemplated that system 10 may be utilized during fabricationonly skeleton 17 and/or only skin 19, if desired. For example, computingdevice 26 may be utilized to monitor ongoing fabrication processes andto selectively adjust process parameters in real or near-real time andachieve better printing of subsequent layers, based on generation ofdata cloud 35 and comparison with the corresponding virtual model(s).That is, the disclosed system and method are not limited to fabricationsof structures having different components that are manufactured inseries. Similarly, instead of only adjusting process parameters,computing device 26 may be utilized to implement measures (to adjusttapers, curvatures, and other tool path trajectories; to add extramaterial to thin or weak areas; to generate supports for excessiveoverhangs; etc.) to account for and/or correct fabricated geometry ofstructure 12 that does not adequately match the virtual model.

It will be apparent to those skilled in the art that variousmodifications and variations can be made to the disclosed system. Otherembodiments will be apparent to those skilled in the art fromconsideration of the specification and practice of the disclosed system.For example, the feedback information and control provided by computingdevice 26 may be used for more than just skinning structure 12. Forinstance, the information and control may be used to generate supportsrequired to sustain portions of structure 12 that deviated from theoriginal model. In another example, although non-contact energy-typereceivers 30 a have been described as useful in generating data cloud35, it is contemplated that contact-type receivers (e.g., tactilereceivers) may alternatively or additionally be used to generate signalsindicative of surface features of structure 12. It is intended that thespecification and examples be considered as exemplary only, with a truescope being indicated by the following claims and their equivalents.

What is claimed is:
 1. An additive manufacturing system, comprising: aprint head configured to discharge a material; a support connected toand configured to move the print head during discharge of the materialto fabricate a structure; a receiver mounted to the print head andconfigured to generate a signal indicative of at least one of a shape, asize, or a location of the discharged material; and a processor incommunication with the receiver and the support, the processor beingconfigured to: generate a data cloud of the structure fabricated by theadditive manufacturing system based on the signal and a known positionof the receiver at a time of signal generation; make a comparison of thedata cloud and a virtual model of the structure; and selectively make anadjustment to the discharge of the material based on the comparison. 2.The additive manufacturing system of claim 1, wherein: the structureincludes a skeleton and a skin fabricated over the skeleton; the datacloud is associated with the skeleton; and the processor is configuredto generate a virtual model of the skin based on the comparison.
 3. Theadditive manufacturing system of claim 1, wherein: the structureincludes a skeleton and a skin fabricated over the skeleton; the datacloud is associated with the skeleton; and the processor is configuredto modify an existing virtual model of the skin based on the comparison.4. The additive manufacturing system of claim 1, further including alight source configured to scan the structure during discharging,wherein the receiver is configured to generate the signal based on animage captured of the scan.
 5. The additive manufacturing system ofclaim 4, wherein: the material includes a continuous reinforcement thatis at least partially coated in a liquid matrix; and the additivemanufacturing system further includes a cure enhancer configured toexpose the liquid matrix to a cure energy.
 6. The additive manufacturingsystem of claim 5, wherein the cure enhancer is the light source.
 7. Theadditive manufacturing system of claim 1, wherein the processor isconfigured to selectively adjust at least one of a cure enhancer, apositioning actuator, a cutter, a liquid matrix supply, or areinforcement supply based on the comparison.
 8. The additivemanufacturing system of claim 1, wherein: when the comparison indicatesa difference less than a threshold, the processor is configured to makethe adjustment to discharging parameters; and when the comparisonindicates a difference greater than a threshold, the processor isconfigured to terminate discharging.
 9. The additive manufacturingsystem of claim 8, wherein when the comparison indicates the differenceis greater than the threshold, the processor is further configured toflag the structure for discard.
 10. The additive manufacturing system ofclaim 1, further including a display, wherein the processor isconfigured to cause a representation of the comparison to be shown onthe display.
 11. The additive manufacturing system of claim 10, whereinthe representation includes the virtual model overlaid with the datacloud.
 12. A method of additively manufacturing a structure, comprising:discharging a material from a print head; moving the print head duringdischarging to fabricate the structure; generating a signal indicativeof at least one of a shape, a size, or a location of the dischargedmaterial; generating a data cloud of the structure during dischargingbased on the signal; making a comparison of the data cloud and a virtualmodel of the structure during discharging; and making an adjustmentduring discharging based on the comparison.
 13. The method of claim 12,wherein: the structure includes a skeleton and a skin fabricated overthe skeleton; the data cloud is associated with the skeleton; thevirtual model is associated with the skeleton; and the method furtherincludes generating a virtual model of the skin based on the comparison.14. The method of claim 12, wherein: the structure includes a skeletonand a skin fabricated over the skeleton; the data cloud is associatedwith the skeleton; the virtual model is associated with the skeleton;and the method further includes modifying an existing virtual model ofthe skin based on the comparison.
 15. The method of claim 12, furtherincluding scanning the structure with light during discharging, whereingenerating the signal includes generating the signal based on an imagecaptured of the scan.
 16. The method of claim 15, wherein: the materialincludes a continuous reinforcement that is at least partially coated ina liquid matrix; and the method further includes exposing the liquidmatrix to a cure energy.
 17. The method of claim 16, wherein the cureenergy is light.
 18. The method of claim 12, wherein making theadjustment during discharging includes selectively adjusting operationof at least one of a cure enhancer, a positioning actuator, a cutter, aliquid matrix supply, or a reinforcement supply based on the comparison.19. The method of claim 12, wherein: when the comparison indicates adifference less than a threshold, the method includes making theadjustment to discharging parameters; and when the comparison indicatesa difference greater than a threshold, the method includes terminatingdischarging and flagging the structure for discard.
 20. The method ofclaim 12, further including showing a representation of the comparisonon a display, wherein the representation includes the virtual modeloverlaid with the data cloud.